Displays include televisions, computer monitors, home cinema displays, digital cinema displays, dedicated displays on devices such as tablet computers, cellular telephones, digital cameras, copiers, industrial controls, specialized displays such as displays for medical imaging, virtual reality, vehicle simulation and the like. Color displays may be used to display color images specified by image data.
Displays may incorporate any of a wide variety of underlying display technologies. For example, displays may comprise: cathode ray tube (CRT) displays; backlit liquid crystal displays (LCDs); plasma displays; organic LED displays (OLED displays); laser projectors; digital minor device (DMD) displays; and electroluminescent displays. Within any of these general technologies a wide variety of different constructions and compositions for light-emitting and/or filtering elements are possible. Different displays may have capabilities that differ significantly in areas such as: the range of different colors (gamut) that can be displayed; the maximum brightness achievable; the contrast ratio; the resolution; the color depth; available dynamic range; the white level, the white point, the black point, the number of grey steps, and the like.
Consequently, the same video content may appear different when played back on different displays. Video content displayed on some displays without modification may depart from the creator's creative intent in one or more ways.
Some current displays can outperform displays that were state-of-the-art at a time when certain video content was created. For example, the displays may be capable of providing images that have brighter highlights, greater contrast, and/or wider color gamuts than legacy displays that were originally available when the video production was created. It would be desirable to take advantage of these improved capabilities without departing significantly from the creative intent embodied in the video content.
It may be desirable to play video content created to take advantage of high-performance displays on legacy displays or displays that have lower capabilities. It would be desirable to provide methods and apparatus for adapting the way that the video is played to preserve as much as possible a creative intent embodied in the video content.
The perception of colour and luminance can be affected by ambient conditions. A video presented under theatre conditions may be perceived by viewers significantly differently when viewed in a location where there is significant ambient light. Further, the characteristics (such as the colour temperature) of ambient light can affect a viewer's perception of video content. It would be desirable to adapt the playback of video content taking into account the environment in which the video content is being viewed to preserve as much as possible a creative intent embodied in the video content.
There is a need to provide viewers of images (including still and/or video images) with viewing experiences that exploit the capabilities of displays on which they view the images. There remains a need for apparatus and methods which may be applied to adjust video signals such that video or other image content encoded in the signals has a desired appearance when played.